2.1.6 - developmental psychology in memory (dyslexia and working memory)

Question 1

what is dyslexia?

Answer 1

a specific learning difficulty which affects one domain of cognition (reading), but leaves other intellectual capacities unaffected

Question 2

what are the effects of dyslexia?

Answer 2

• individuals struggle to read accurately and fluently
• they have normal levels of comprehension
• they may also struggle with writing and spelling

Question 3

how common is dyslexia?

Answer 3

• it affects between 4% and 8% of children in English-speaking countries
• it is more prevalent in boys than girls

Question 4

what are signs of dyslexia?

Answer 4

• early signs include delayed speech and jumbling words and phrases
• when children begin education, signs may include difficulty learning the names of letters and sounds, inconsistent spelling and slow reading

Question 5

what are potential causes of dyslexia other than problems with cognition?

Answer 5

• genetics
• environmental factors eg. exposure to written material at home

Question 6

what does the simple theory of reading (Gough and Tunmer, 1986) suggest?

Answer 6

• reading involves two processes, decoding and comprehension
• the processes occur in working memory which has limited capacity
• decoding involves translating the letters and words on a page into words in a reader’s head
• comprehension involves understanding the meaning of the words, phrases and sentences

Question 7

how is working memory involved in learning to read?

Answer 7

• when people learn, most of wm capacity is used to learn relationships between letter shapes and sounds (decoding), leaving little capacity to understand complex stories (comprehension)
• as people get more practice at decoding, it becomes more automatic and less reliant on working memory, leaving more capacity for comprehension

Question 8

how is decoding different in individuals with dyslexia?

Answer 8

• they don’t develop automacity, so it remains a slow and error-prone process for them to translate the words on a page into internal language (decoding)
• this leaves less capacity for comprehension

Question 9

what does the simple theory of writing suggest?

Answer 9

• writing involves two processes - encoding and planning
• encoding involves converting the words in someone’s head into letter and words on a page
• planning involves deciding what will be included in the writing and how it will be structured

Question 10

how is encoding different in individuals with dyslexia?

Answer 10

• they don’t develop automacity, so it remains slow
• this leaves less capacity for planning

Question 11

how might working memory function differently in individuals with dyslexia?

Answer 11

• De Jong (2006) and Henry (2012) argue that the phonological loop (which processes and manipulates speech-based information) may develop differently
• this makes it harder to learn letter-sound correspondences and sequence sounds correctly

Question 12

what are examples of supporting evidence for dyslexia being caused by differences in working memory?

Answer 12

• Henry (2012) - dyslexic children have shorter word and digit span than non-dyslexic children and performed poorly on tasks involving sequential word recall (below average PL functioning)
• Smith-Spark et al. (2010) - dyslexic adults had unimpaired visuo-spatial sketchpad but impaired phonological loop compares to control group of non-dyslexic adults
• Alloway et al. (2013) - training dyslexic children in working memory strategies improves academic performance

Question 13

how can cross-cultural comparisons support the idea that dyslexia is caused by differences in working memory?

Answer 13

• dyslexia is more common in countries with writing systems where relationships between written characters and sounds are inconsistent and complex
• Wydell (2012) - dyslexia rates are lower in Japan which has shallow orthography (each character represents one syllable) compared to England which has a deep orthography (some letters/letter combinations represent different sounds)

Question 14

what are limitations of using working memory to explain dyslexia?

Answer 14

• it may not provide a complete explanation - dyslexia is still present in countries like Japan with shallow orthographies so phonological loop differences may not be the only cause, and we don’t know why these differences occur
• dyslexia is often comorbid with other learning difficulties so the interaction between these can make it hard to isolate differences in phonological loop as the cause for reading impairments